PURPOSE: The purpose of this study was to evaluate the role of cardiac magnetic resonance imaging (MRI) in the follow-up of patients with Fabry disease. Our hypothesis was that LV functional parameters and native myocardial T1 and T2 values could be used to monitor treatment efficacy. MATERIALS AND METHODS: This prospective, observational, multicenter study included patients with Fabry disease who underwent two cardiac MRI examinations performed at 1.5 T 24 months apart at five University Hospitals between March 2017 and December 2022. Changes in cardiac MRI parameters were compared between two groups of patients according to whether or not they were receiving specific treatment. RESULTS: Twenty-six patients with Fabry disease were enrolled. There were 17 women and 9 men, with a mean age of 45.3 ± 17.4 (standard deviation [SD]) years. Both treated and untreated patients showed an increase in native T1 values over time, but the T1 increase was higher in treated patients (global T1, +39.4 ± 28.9 [SD] ms) than in untreated ones (global T1, +14.5 ± 30.3 [SD] ms) (P = 0.04). T2 values decreased in treated patients (global T2, -2.11 [SD] ms ± 3.36 but increased in untreated ones (global T2, +0.57 ± 1.63 [SD] ms) (P = 0.02). No significant changes in extracellular cardiac volume, left ventricular functional parameters, late gadolinium enhancement or left atrial volume were observed. However, LV mass index increased in untreated patients and decreased in treated patients. Intra- and interobserver reproducibility of T1 measurements showed mean biases of -0.18 ms (limit of agreement:11.61, 11.24) and -0.64 ms (limit of agreement:23.82
22.54), respectively. CONCLUSION: Variations in native myocardial T1 values at cardiac MRI are significantly greater in patients with Fabry disease receiving treatment than in untreated patients, suggesting an effect of treatment on lipid storage. In addition, changes in T2 values suggest an anti-inflammatory effect of the treatment.